In 1966 (or so I've been told), Roger Zelazny seemed like the future of science fiction. He was one of a progressive breed of SF writers who came to be known as "the new wave" in homage to the French film directors who were said to have influenced them. These authors were generally characterised by a determination to move the genre away from its pulpy origins, to tackle difficult political issues and use sophisticated literary devices to do so.

The story, for instance, boils down to a standard cold-war mix of nuclear paranoia and alien invasion fear, even if it initially seems completely out there. It's set on a future earth, some years after a near-apocalyptic nuclear war. Most of the mainland has been destroyed, but life still continues on islands – albeit complicated by the presence of various mutants (mainly based on mythological creatures) who have grown up around radiation hotspots, and by a race of blue aliens – the Vegans – who seem intent on buying up the Earth as real estate. The narrator is a superhuman of considerable (but unspecified) age who likes to be called Conrad, but seems to have many other names. He was once a revolutionary determined to blow up everything to do with the Vegans and Earth-folk who live "off-planet" , but who now acts as a kind of caretaker of Earth's remaining historical sites and ends up fighting to protect a Vegan called Myshtigo from a superhuman assassin in the pay of a group inspired by his own revolutionary past …

It's all as breathless and convoluted as that last paragraph. Characters appear and disappear with alarming rapidity; often dozens of them at a time at exotic cocktail parties that could have come straight out of a 1960s article about jet-set living (but for the aliens). The scenes chop and change with the manic rapidity of Godard at his most relentless. New types of monsters and mutations are introduced with barely a line apiece and vast chunks of history essential to the story are dealt with in seconds.

Zelazny has enough skill to keep things on just the right side of bewildering, but the rocky ride is rarely entirely pleasurable, thanks to the other major dating factor on the novel: Conrad's no-longer-achingly-hip narrative voice.

Consider:

"I drank a pint of rum in an effort to catch up, but I couldn't. Myshtigo kept taking sips of Coke from a bottle he had brought along with him. No one noticed that he was blue, but then we had gotten there rather late and things were pretty well along the way to wherever they were going."

'I wonder ...' I said, and left the part of her face that I could see wearing a rather funny expression as we walked along."

I'm sure you can imagine how irritating it gets after a while, and how easy it is to lose patience with This Immortal. This is a shame, because it does have plenty to offer. Although none of the characters have anything approaching a rounded personality, Zelazny cleverly builds intrigue around them using determinedly vague allusions to their long histories, odd powers, and convoluted love lives. I didn't believe in Conrad, or like him, but I did start to find him fascinating. There is also plenty of strange and beautiful writing about the Vegans and their different perceptions that allow them, say, to see different aspects of a "white" flower since their eyes can process more light wavelengths and so look "deeper" into ultraviolet.

Zelazny's future world, where mutant humans, blue aliens, mythological creatures and supermen collide, also allows him to build some joyously over-the-top scenarios. The climactic showdown has to be one of the most absurd in literature. Think One Million Years BC, crossed with Dracula, Heart of Darkness (complete with learned Kurtz references), Gladiator and the Texas Chainsaw Massacre and you're on the way to encompassing its lurid weirdness. Or at least, you are if you also factor in the arrival of a gigantic millennia-old dog with skin harder than armour who leaps into the fray at the last minute …

It's just a shame that it's such a slog to get to that gleeful stage, and it's hard to imagine anyone reading the book now except out of historical curiosity.